Setting up different Items to be used in EAM

We are using R12.2.10 and the Items that have been setup to be used on Work Orders in EAM are primarliy MRO types that are Stocked in Subinventories. We want to add more Items that are best described as Critical Spares and Capital Spares that will also be setup as Stocked in Subinventories. These will need to be distinquished from the MRO types that will have similiar attributes. Is it best to do this setup using different Item Types or Category Sets or Item Catalogs? Or is there some other feature that we should be looking at for this setup?